Thursday, August 14, 2014

The Flue Gas Cleaning Cycle

Guest Blogger: Paul Campo, Product Marketing Intern

Flue gas is the exit gas from a combustion system that is discharged into the atmosphere.  There is often a necessity to clean the flue gas according to environmental regulation standards before it is vented to the surroundings.

Flue gas treatment is a common pollution control system installed in many chemical manufacturing plants.  In mining applications, cleaning systems (such as above) can be used to purge undesired gasses released during the ore roasting process, mainly CO2 and nitrogen, and collect the mineral dust. The flue gas exiting each roaster is first fed through a multiclone (cluster of cyclones) to remove large particles. The recovered material from the cyclones re-enters the roasters via the paddle mixers.

An induced draft fan draws the flue gas out of the cyclones and transfers it to the electrostatic precipitators (ESPs). The electrostatic precipitators enable the removal of ultra-fine particles from the flue gas that the cyclone was unable to separate. The clean flue gas consisting mainly of carbon dioxide, water vapor and nitrogen is then vented through a central stack to the atmosphere.  The ore dust collected by each of the electrostatic precipitators is conveyed by screw or chain to the dust hopper where it is transferred to the storage silo.

Flue gas cleaning systems are important industrial processes ranging anywhere from hazardous material incineration to crude ammonia liquor production.  Optimization of flue gas temperature control may significantly improve electrostatic precipitator performance, enabling higher load generation.  The importance of maintaining flue gas temperature in a stable operating range is to avoid increased resistivity and gas volume due to higher temperatures, which can have a deleterious effect on ESP performance (Neundorfer Inc, p.2).  Controllers designed with model-predictive technology, or advanced process control (APC), are used to compute optimal adjustments and minimize deviation from the target profile of the roasters. This is just one of the ways that SimSci APC can reduce your energy costs.

In addition, Schneider Electric offers process optimization with APC for the following mining applications:
  • Crushers
  • Grinding Circuits
  • Mineral Flotation
  • Thickening and Water Management
  • Hydrometallurgy (Solvent Extraction)
  • Electrowinning/ Electrorefining
  • Copper Converter 
  • Nickel Reduction Shaft Furnaces 
Check out our short promotional video to learn more and sign up for your free consultation here.